1. Technical Field
The present disclosure relates to a method for making cathode slurry.
2. Description of Related Art
A field emission cathode is an important element for a field emission device. A field emission cathode is usually made by printing a cathode slurry including a plurality of electron emitters on a cathode conductive layer and exposing the electron emitters from the cathode slurry.
Carbon nanotubes (CNT) are very small tube-shaped structures, and have extremely high electrical conductivity, very small diameters, and a tip-surface area near the theoretical limit. Thus, carbon nanotubes can transmit an extremely high electrical current and be used to make cathode slurry. The cathode slurry based on carbon nanotubes is usually made by dispersing carbon nanotubes in organic solvent by ultrasonic vibrating to form a first mixture, dispersing indium tin oxide (ITO) particles and glass powder in organic solvent by ultrasonic vibrating to form a second mixture, mixing the first mixture and the second mixture with an organic carrier to form a third mixture, and vaporizing the third mixture to remove the organic solvent to obtain cathode slurry based on carbon nanotubes. However, the viscosity and plasticity of the cathode slurry is difficult to control because the vaporizing time and temperature should be controlled accurately according to the weight percentage of the ingredient. If the vaporizing time is too long and the temperature is too high, the viscosity of the carbon nanotube cathode slurry will be too high and the carbon nanotube cathode slurry will be less liquid. If the vaporizing time is too short and the temperature is too low, the carbon nanotube cathode slurry will be less plastic.
What is needed, therefore, is to provide a method for making a cathode slurry that can overcome the above-described shortcomings.